Large-scale, ground-mounted solar projects require many acres of land to produce electricity, with single projects reaching hundreds of megawatts and counting. Industry organizations estimate the total amount of land it would take to power the entire United States with solar is between 10 million and 11 million acres — not considering other solar siting locations like rooftops and parking lot carports.
Even with the push for more rooftop solar, millions of acres will still be developed for solar production to pursue the Biden Administration’s ambitious goal to transition from fossil fuel-powered energy generation by 2035. Solar developers have a choice for how they will prepare and manage this land that will be covered in solar panels.
Silicon Ranch, a solar developer based in Nashville, Tennessee, has changed its approach to PV project site preparation through its land management subsidiary, Regenerative Energy. As its name suggests, Regenerative Energy employs environmentally friendly, regenerative land management methods like sowing native seed crop and introducing livestock to solar project sites to ensure their longevity.
Tyler Huber, agrivoltaic technician with Silicon Ranch, talked with Solar Power World about regenerative land management, explaining how millennia-old practices like shepherding can still complement contemporary technologies.
SPW: What is Regenerative Energy’s origin story?
Huber: As the long-term owner and operator of every project in our portfolio, we stand behind the performance of each of our solar farms around the clock. Initially, Silicon Ranch viewed the vegetation under our panels the same way the rest of the industry did, as a liability rather than an asset. In 2018, that mindset changed when Silicon Ranch’s co-founder and CEO, Reagan Farr, met with my former employer — who just so happens to be one of the world’s most renowned regenerative ranchers — Will Harris of White Oak Pastures.
Will had reached out to Reagan as a concerned neighbor of a future project and was worried that the company would be employing conventional practices, like using pesticides, next to Will’s ranch, which had been operating regeneratively for decades. Using conventional pesticides and “regenerative” practices aren’t exactly consistent with each other. After meeting with Will, Reagan became a major proponent of regenerative land management and recognized that the solar industry is going to be responsible for a large amount of land over the coming years. He took that word “responsible” seriously.
Once our leadership had also spoken with Will and looked further into the subject, we saw an opportunity to improve the land under our panels by marrying solar energy generation with regenerative land management practices that promote long-term, deep-rooted vegetation and plant growth cycles while supporting economic development in the communities where these projects are located.
How do you approach building out a proper land management plan for a brand-new solar project?
To implement agrivoltaics, it is important to think holistically about the project by first carefully observing the land as it currently is and by being ready to adjust to changing conditions.
I am fortunate to work with some brilliant people who have managed their own property for years. It is a team effort, between our in-house agrivoltaic technicians and world-renowned regenerative ranching partners, to plan and execute the land management operational strategy.
Ideally, when starting out, we have some input during the construction phase as to what seeds to plant and when to plant them. Erosion control throughout construction and for the life of the project is a high priority.
This includes establishing multi-species grasses in advance of construction. By doing so, we are able to improve soil health during construction, provide vegetation for possible grazing animals where appropriate and continue to do so throughout the life of the facility. We also build arrays higher off the ground or put guards around trackers, so they do not get bumped into by grazing sheep.
We select vegetation varieties that offer multiple benefits to the land and to the livestock. Sheep don’t control 100% of the vegetation, so we need to have a mowing plan in place that specifies what type of equipment is needed. We basically develop a toolkit unique to each site and its ecoregion to help us get the land where we want it to be, which includes sheep, mowing equipment, seed and hay/feed. We also understand the importance of demonstrating the impacts of these efforts in a credible, transparent way, which is why our Regenerative Energy projects are third-party verified.
How do you ensure the seed mix you’re planting and the animals you’re grazing are appropriate for the project?
When making the decision on how to stock a site with sheep, the first thing we do is gather as much information about the site as possible, including plant density, type of soil, history of the land prior to solar installation, climate and what type of forage species are growing there.
Then, I will present these findings to my friends and colleagues to discuss what I have seen. There is no one-size-fits all approach, and there are often factors we can’t control for, but previous experience helps outline a plan with acceptable risk, animal performance and animal impact on the land.
Stocking densities need to be managed and adjusted regularly, based on the desired outcome. When the flock has higher nutritional needs (ewes with lambs nursing, for example) we will often reduce the density to allow more selective grazing. This decision comes with a tradeoff: We will likely have to mow behind the animals because a group of fewer sheep that’s allowed to be more selective is less likely to sufficiently eliminate the less desirable, less nutritious pasture species.
When we are managing a group with lower nutritional requirements, such as dry ewes or wethers, we can get better vegetation management results. By running them at higher densities, we can get them to eat and trample species they wouldn’t otherwise impact. These species are often lower in nutritional value, and we are always prepared to supplement as necessary to ensure the sheep stay healthy. We can justify the added cost of supplementation because we aren’t firing up mowers to clean up pasture species that’ve been left behind.
What are the benefits of going this route over other site preparation methods?
I would say the biggest advantage I’ve seen has come from our choice to plant our seed mix once the land has been cleared. Establishing desirable vegetation early on is a huge advantage post-construction as it creates new benefits for solar projects, including healing degraded soils, improving ecosystem function and increasing biodiversity of both plants and wildlife.
And this planting doesn’t have to be specific to the purpose of grazing — you can choose a seed mix that will be low-growing and fast-establishing for erosion control. I have a hard time looking at any vegetation and not considering how my sheep would graze it, though.
How do you prepare sites for animal grazing, and how do you support the sheep on-site?
Maintaining the site after construction begins with identifying problem areas: Where might mowers get stuck? Where is the vegetation the thinnest? Are there potential erosion concerns? And so on. There are other things to consider when introducing livestock into the equation, too — we need to source clean drinking water, good hay for winter and local supplies for supplemental feed, which is sometimes needed when lambing on pasture.
When first starting out on a site, you will need to identify what is already growing there and whether the sheep will be able to control it or not. The ability for the sheep to be successful depends on the shepherd. The number of sheep per acre grazing a given paddock will determine the flock’s impact on the vegetation. Whatever is left over may need to be mowed. No matter what is left behind by the sheep, it is always easier to mow the residual vegetation after grazing than to mow it with no help from the sheep.
Labor is a big consideration to determine how you want to manage the site, as is the maintenance required for the mowing equipment. The most important consideration is the health and welfare of the flock. Typical threats like internal parasites along with other factors also need to be guarded against to maintain a healthy flock.
What advice would you give to a solar installation company interested in implementing regenerative land management practices?
The best time to start is now! Results from adopting these practices do take time, but the faster you start implementing regenerative practices, the faster the benefits will begin coming to fruition. And these benefits shouldn’t be understated; they include benefits to the land, sheep, wildlife, solar project itself and surrounding community for many years to come. Creating biologically active soil will help grow better forage and reduce the growth of weeds that, when not managed, can shade the solar panels and negatively impact their performance. The livestock benefit from the opportunity to graze more and eat healthier vegetation.
All of this allows the project itself to benefit from less frequent mechanical mowing and new revenue streams from livestock sales. The benefits also come full circle to the local community, providing new job opportunities for not only aspiring ranchers without access to their own land — including myself and some of my colleagues — but also ancillary industries supporting regenerative agriculture. Regenerative sheep grazing can also create a new source of locally grown, nutrient-dense food that can be enjoyed by people in the surrounding community. And it’s scalable!